RU59258U1 - DEVICE OF ULTRASONIC CONTROL OF HIGH VOLTAGE VOLTAGE INSULATORS - Google Patents

Abstract

The device relates to electrical engineering and is intended for remote diagnostics of insulators of a contact network of live railways, high-voltage power lines, power plants and substations, etc. The principle of its operation is based on the detection and analysis of ultrasonic signals accompanying spark and corona discharges.

The device contains a receiver of ultrasonic vibrations with a wide radiation pattern, a laser pointer, an optical sight, an amplifier-converter of ultrasonic vibrations, blocks of automatic and manual gain control, a digital voice recorder, control head phones, a liquid crystal indicator and differs in that it additionally contains a receiver of ultrasonic vibrations with a narrow radiation pattern and digital signal processing unit, configured to correlate the analysis of the spectra of incoming signals with exemplary spec ramie different types of bits contained in the non-volatile memory.

The device improves the accuracy and reliability of determining the location of defective places in live insulators.

Description

The device relates to electrical engineering and is intended for remote monitoring of electrical equipment in order to detect surface partial discharges and cracks in the insulators of the contact network of railways, high-voltage power lines, power plants and substations, as well as control the disconnector connections, the quality of contacts in power distribution boards, etc.

Currently, the condition of high-voltage insulators under voltage is monitored by measuring rods or remote control devices [1] (Yu.V. Bogdanov, V. G. Rogatsky Vestnik VNIIZhT, 2003, No. 3, 28-30 s).

Detection of garlands of suspended insulators under voltage with a measuring rod is very laborious and quite dangerous.

Known ultrasonic detector UD-8M [2] (Passport and user manual UD-8M, Nizhny Novgorod, 1992, Signal LLP), designed for remote location of leaks in insulators of the contact network of railways and power lines. The detector’s principle of operation is based on the detection of ultrasonic (US) signals accompanying spark and corona discharges. By directing the detector to the places of probable location of spark and corona discharges, the noise level in the head phones is monitored. The detector is oriented to the maximum of this noise. The disadvantages of the detector are its low sensitivity and a large opening angle, which does not allow to accurately determine the location of the source of ultrasonic noise.

The Ingula acoustic ultrasonic detector has somewhat better characteristics [3] (Inventor and Rationalizer of 2003 No. 10),

containing, in addition to headphones, a linear light indicator and an optical sight.

The location of the defect is determined by the maximum noise level in the head phones and the maximum number of luminous fragments of the linear indicator. However, this detector also has a sufficiently large aperture angle, which does not allow to accurately determine the location of the source of ultrasonic signals, for example, in garlands of suspended insulators.

Closest to the proposed device is a device for ultrasonic testing of high-voltage insulators under voltage [4] (patent for invention RU 2262100. G 01 No. 29/04), adopted as a prototype.

The device [4] contains an ultrasonic detector, an optical sight, a linear light indicator, a laser pointer, an integrated power source, a digital voice recorder, an automatic sensitivity adjustment unit for receiving a signal from an ultrasonic detector. In this case, the output of the automatic sensitivity adjustment unit is connected to the input of the ultrasonic signal processing unit, configured to transfer the processing results together with voice recorders to the long-term memory unit with subsequent transfer to a computer.

The device [4] has several advantages compared to [3]. However, even having a sufficiently large aperture angle (of the order of 3 °), it does not allow to accurately localize the source of ultrasonic noise radiation (location of the defect).

To improve the accuracy and reliability of determining defective places, we propose a device for ultrasonic monitoring of high-voltage insulators under voltage, including an ultrasonic vibration receiver with a wide radiation pattern, an optical sight, a laser pointer, a liquid crystal indicator, an ultrasonic oscillation converter, automatic and manual gain control units, digital voice recorder

telephones, a computer communication interface, a built-in power supply, characterized in that it further comprises a ultrasonic vibration receiver with a narrow radiation pattern, for example, a parabolic reflector with an ultrasound microphone placed in its focus with a radiation pattern of about 1 °, and a digital processing unit a signal containing a normalizing amplifier, an analog-to-digital converter (ADC), a fast Fourier transform unit (FFT), a digital correlator, a non-volatile memory unit with model spectra, a digital co mparator, control device and sound annunciator.

To point to the object under examination and its visual control in the proposed device, a video screen can be integrated, which increases the usability and eliminates the laser target designator and optical sight.

Figure 1 presents the structural diagram of the proposed device. Here 1 is a receiver of ultrasonic vibrations with a wide radiation pattern, 2 is an optical sight, 3 is a laser target designator 4 is a receiver of ultrasonic vibrations with a narrow radiation pattern, 5 is an input switch, 6 is an amplifier-transducer of ultrasonic vibrations, 7 is a digital voice recorder, 8 is control headphones, 9 - automatic / manual gain control switch, 10 - manual gain control, 11 - digital signal processing unit, 12 - liquid crystal display, 13 - sounder, 14 - test object, 15 - built-in power supply (on Heme not shown).

In Fig.2 presents a structural diagram of a block of digital signal processing 11 (see Fig.1). Here 11.1 is a normalizing amplifier, 11.2 is an ADC, 11.3 is an FFT block, 11.4 is a digital correlator, 11.5 is a non-volatile memory block with exemplary spectra, 11.6 is a digital comparator, 11.7 is a control device.

Figure 3 shows a view of garlands of four plate insulators examined by the proposed device.

The device operates as follows. The input switch 3 includes a receiver 1 ultrasonic vibrations with a wide radiation pattern. Using a laser pointer 3 or a video screen, the device is guided to various sections of the object being examined 14. The signals detected by the receiver 1 are transmitted to the ultrasonic vibration amplifier 6, the output of which is connected to the input of the digital signal processing unit 11. The signals received in block 11 , undergo special processing, including using correlation analysis with sample spectra of various types of discharges from block 11.5 non-volatile memory. If the conclusion about the presence of a defect follows from the results of the analysis, the sound siren automatically turns on. Correlation analysis of the spectra of the received signals excludes the possibility of erroneous conclusions associated with extraneous noise sources that are not signs of a defect.

To determine the exact position of the source of ultrasonic noise in the area detected by the receiver 1, the input switch 5 includes a receiver 4 of ultrasonic vibrations with a narrow radiation pattern and determine the position of the source of ultrasonic signal in this area by the signal of the siren 13 and the maximum signal level displayed on the liquid crystal display 12 . Additionally, the ultrasound signal can be monitored by ear control headphones 8.

With strong background noise, which interferes with the accurate localization of the ultrasonic noise source, switch 9 switches to manual gain control (attenuation).

The digital voice recorder 7 records comments about the object being checked (number, object location, defect location, etc.) and, if necessary, the ultrasound signal itself emitted by the object being examined. These records can be transferred to the computer via the communication interface.

The combined use of two ultrasound oscillation receivers with a wide and narrow radiation pattern in the device increases the speed and accuracy of determining the location of the defect (discharge source), and the correlation analysis of the signals from the objects under study with the sample discharge spectra contained in non-volatile memory eliminates the possibility of errors due to the presence of extraneous noise.

When using an ultrasonic receiver with a narrow radiation pattern, the level of reception of ambient noise is reduced, which makes it possible to identify sources of ultrasonic noise at a greater distance in comparison with the applied analogues.

Example.

The proposed device was tested at the Altai distance power supply of the West Siberian Railway. Suspended garlands of four glass plate insulators of a direct current contact network were diagnosed. The view of these garlands is shown in figure 3.

A total of 120 garlands were examined. Of these, two were found to be defective. In this case, it was clearly revealed which of the four plate-shaped insulators in this garland is defective.

Claims (1)

A device for ultrasonic (ultrasound) monitoring of high-voltage insulators under voltage, including a receiver of ultrasonic vibrations with a wide radiation pattern, an optical sight, a laser target indicator, a liquid crystal indicator, a built-in power supply, an amplifier-converter for ultrasonic vibrations, a digital voice recorder, and control headphones, characterized in that it additionally contains a ultrasonic vibration receiver with a narrow radiation pattern, the output of which through the input switch is connected to the input of the amplifier-converter I have ultrasonic vibrations, the output of which is connected to the input of the digital signal processing unit, which contains a series-connected normalizing amplifier, an analog-to-digital converter (ADC), the fast Fourier transform unit (FFT), a digital correlator, a digital comparator, the output of which is connected to the input of a sound siren and control device, the output of which is connected to the second input of the ADC, the second input of the FFT unit, the input of the non-volatile memory unit with exemplary spectra, the output of which is connected to the second input of the digital corrector the radiator, and the input of the liquid crystal indicator.